Derivative Instruments and Hedging Activities - Part 2 (Details) - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Liabilities
Derivative Liabilities, Gross	$ 241	$ 315
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	349	348
Other Current Assets [Member]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	82	84
Other Current Liabilities [Member]
Liabilities
Derivative Liabilities, Gross	72	211
Other Noncurrent Assets [Member]
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	267	264
Other Noncurrent Liabilities [Member]
Liabilities
Derivative Liabilities, Gross	169	104
Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	208	138
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	76	57
Not Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	33	177
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	273	291
Interest Rate Contract [Member]
Liabilities
Derivative Liabilities, Gross	182	262
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	54	15
Interest Rate Contract [Member] | Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	179	125
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	53	15
Interest Rate Contract [Member] | Not Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	3	137
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	1	0
Cross currency derivatives [Member]
Liabilities
Derivative Liabilities, Gross	3	3
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	23	29
Cross currency derivatives [Member] | Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	3	3
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	23	29
Cross currency derivatives [Member] | Not Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	0	0
Foreign Exchange Contract [Member]
Liabilities
Derivative Liabilities, Gross	51	30
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	248	269
Foreign Exchange Contract [Member] | Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	26	1
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	0	8
Foreign Exchange Contract [Member] | Not Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	25	29
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	248	261
Commodity Contract [Member]
Liabilities
Derivative Liabilities, Gross	5	20
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	24	35
Commodity Contract [Member] | Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	0	9
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	0	5
Commodity Contract [Member] | Not Designated as Hedging Instruments [Member]
Liabilities
Derivative Liabilities, Gross	5	11
Derivative Asset, Fair Value, Amount Not Offset Against Collateral [Abstract]
Derivative Assets, Gross	$ 24	$ 30